This Small Business Technology Transfer Phase I project will develop an innovative thermal solution to cool underwater acoustic projectors. More efficient cooling of the acoustic projectors will allow the devices to run at longer duty cycles, higher output powers and with longer service life. Current acoustic projectors use thermal conduction through the transducer parts to dissipate the waste heat to a surrounding water sink. For past applications at lower powers and duty cycles, this thermal management approach has been sufficient to maintain the acoustic performance. Stress and electric field limits tend to be more of an issue at these operating conditions. As the Navy requires higher duty cycles (>10%) and power outputs from the transducers, the thermal limit becomes of greater concern. Advanced Cooling Technologies, Inc. (ACT) and Pennsylvania State University’s Applied Research Lab (ARL) propose to develop a heat pipe assisted thermal solution to increase the effective thermal conductivity of the transducer so that the transducer can operate at lower temperatures.